[40] See p. 314. Marx did not find himself in this dilemma because he held that there is a fundamental 'contradiction' in capitalism which shows itself in a strong tendency for the rate of profit on capital to fall as technical progress takes place. But Rosa Luxemburg sees that the tendency to a falling rate of profit is automatically checked and may even be reversed if real-wage rates are constant (p. 338). [41] See p. 217, note. [42] One passage suggests that she sees the problem, but thinks it irrelevant to the real issue (p. 342). [43] See p. 338. [44] See p. 337. [45] In this model the rate of exploitation is different in the two departments. This means that the numbers represent money value, not _value_. [46] Rosa Luxemburg seems to regard this process as impossible, but for what reason is by no means clear (p. 341). [47] See p. 352. [48] See p. 352. [49] See p. 358. [50] See p. 370. [51] See p. 428. [52] See p. 435. [53] See p. 421. [54] See p. 455. [55] See p. 387. [56] Hicks, _Value and Capital_, p. 302, note. Mr. Hicks himself, however, regards the increase in population as the mainspring. [57] Cf. _A Survey of Contemporary Economics_ (ed. Ellis), p. 63. _SECTION ONE_ THE PROBLEM OF REPRODUCTION _CHAPTER I_ THE OBJECT OF OUR INVESTIGATION Karl Marx made a contribution of lasting service to the theory of economics when he drew attention to the problem of the reproduction of the entire social capital. It is significant that in the history of economics we find only two attempts at an exact exposition of this problem: one by Quesnay, the father of the Physiocrats, at its very inception; and in its final stage this attempt by Marx. In the interim, the problem was ever with bourgeois economics. Yet bourgeois economists have never been fully aware of this problem in its pure aspects, detached from related and intersecting minor problems; they have never been able to formulate it precisely, let alone solve it. Seeing that the problem is of paramount importance, their attempts may all the same help us to some understanding of the trend of scientific economics.